function Hv = H( alpha, beta )
k = [cos(alpha)*cos(beta); % Unit vector
cos(alpha)*sin(beta);
sin(alpha)];
r{1} = [0 0 0]; % Antenna's radius-vector, lambdas
r{2} = [1/4 0 0];
r{3} = [1/8 -sqrt(3)/8 0];
r{4} = [-1/8 -sqrt(3)/8 0];
r{5} = [-1/4 0 0];
r{6} = [-1/8 sqrt(3)/8 0];
r{7} = [1/8 sqrt(3)/8 0];
phi = nan(7,1);
for i = 1:7
phi(i) = 2*pi * r{i} * k;
end
Hv = exp( 1i * phi );
end

